Carbon-Supported Pt-Based Alloy Electrocatalysts for the Oxygen Reduction Reaction in Polymer Electrolyte Membrane Fuel Cells: Particle Size, Shape, and Composition Manipulation and Their Impact to Activity

In the paper

“The formation of Ptalloying can result in two key changes favorable to the enhancement of Pt-alloy catalysts.One is that the alloying of Pt might change the electronic properties of Pt while the other is that the adsorption properties of Pt may be altered by alloying Pt, which is closely related to ORR. 133”

What the sources say

• Supported

  Section 3.2 (p. 10) states that alloying Pt with base metals may alter platinum’s adsorption properties and enhance Pt-alloy catalyst activity. Section 2.1 (p. 5) links changed adsorption properties after Pt alloying to enhanced ORR electrocatalytic activity. (LLM, conf=0.94)

  cites [133] Bing Y., 2010, Chem. Soc. Rev. source

In the paper

“The formation of Ptalloying can result in two key changes favorable to the enhancement of Pt-alloy catalysts.One is that the alloying of Pt might change the electronic properties of Pt while the other is that the adsorption properties of Pt may be altered by alloying Pt, which is closely related to ORR. 133”

What the sources say

• Supported

  Section 3.2 (p. 10) explicitly says that alloying Pt with base metals might change platinum's electronic properties. It also describes altered adsorption properties as a second possible change relevant to catalyst activity. (LLM, conf=0.95)

  cites [133] Bing Y., 2010, Chem. Soc. Rev. source

In the paper

“In addition to the use of protecting agents, pH control is another strategy that can help to control particle size in the synthesis of Pt-based nanoparticle catalysts.”

What the sources say

• ?Not checked — no full text of the sourcecites [223] Shimazaki Y., 2005, J. Colloid Interface Sci. source
• Partly supported

  The 'Effects of synthesis parameters' section says that pH during irradiation synthesis helps determine metallic nanoparticle size, supporting the general strategy. The paper does not establish this specifically for Pt-based nanoparticle catalysts; its 'Effect of pH of the medium' section discusses copper ions and silver clusters instead. No page numbers are available in our copy. (LLM, conf=0.85)

  cites [224] Abedini A., 2013, Nanoscale Res. Lett. sourceExperimental — accuracy not yet measured

In the paper

“It was found that controlling the composition by fine-tuning the stoichiometric ratio of all the metal precursors (i.e., the ratio of Pt to other metals) had direct impacts on the ORR activity, the selectivity, and the durability of Pt-alloy catalysts.147,[425][426][427][428][429][430]”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source
• Partly supported

  The introduction (p. 3) links alloy composition to desirable ORR catalytic properties, including activity, durability and selectivity. The experiments (pp. 3–5), however, tune Ni core size rather than the Pt-to-other-metal precursor ratio; they report activity differences and a stability test, but do not show that fine-tuning precursor stoichiometry directly changes selectivity or durability. (LLM, conf=0.84)

  cites [425] Zhang S., 2014, J. Am. Chem. Soc. sourceExperimental — accuracy not yet measured
• ?Not checked — no full text of the sourcecites [426] Hernández-Fernández P., 2007, J. Phys. Chem. C source

In the paper

“They found that after dealloying the Pt:Cu molar ratio had changed from 0.3 to 1.8 due to the removal of copper in the dealloying process.”

What the sources say

• Supported

  The Results and Discussion section (“Synthesis and Chemical Characterization”) states that the as-reduced and annealed materials had a Pt-to-Cu molar ratio of 0.3, and that dealloying removed a significant fraction of copper, yielding a Pt/Cu ratio of 1.8. (LLM, conf=0.95)

  cites [281] Dutta I., 2010, J. Phys. Chem. C source

In the paper

“However, the large-scale implementation of fuel cell technology for use in commercial residential or transportation applications is hindered largely by the high cost associated with platinumbased electrocatalysts, 12,13 which account for over 55% of the total cost.14”

What the sources say

• ?Not checked — no full text of the sourcecites [12] Peng Z., 2009, Nano Today source
• ?Not checked — no full text of the sourcecites [13] Gasteiger H. A., 2005, Appl. Catal. B: Environ. source
• ?Not checked — no full text of the sourcecites [14] Lin X., 2012, Anal. Chem. source

In the paper

“At the current stage of technology, Pt-based nanoparticles, 15 which are usually supported on porous carbon particles, are the only electrocatalysts presently used in applied PEMFCs, since among all pure metals, platinum supported on carbon has the highest catalytic activity for the oxygen reduction reaction (ORR).[15][16][17][18][19][20][21][22]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [15] Appleby, A. J.InThe Electrocatalysis of Fuel Cell Reactions;Dudley, R.; O’Grady, W.; Srinivasan, S., Eds.; The Electrochemical Society Softbound Proceedings Series, PV 79–2, Princeton, NJ, 1979; p23.

In the paper

“At the current stage of technology, Pt-based nanoparticles, 15 which are usually supported on porous carbon particles, are the only electrocatalysts presently used in applied PEMFCs, since among all pure metals, platinum supported on carbon has the highest catalytic activity for the oxygen reduction reaction (ORR).[15][16][17][18][19][20][21][22]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [15][16][17][18][19][20][21][22]

In the paper

“Alloying has become an attractive strategy to develop advanced Pt-based electrocatalysts, [23][24][25][26][27][28][29] in which the addition of another metal can form a Pt alloy 30 and thus alter the availability of active surface sites (the ensemble effect) or the binding strength of reactants, intermediates, products, and spectator species (the electronic and/or strain effect).31”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [23][24][25][26][27][28][29]

In the paper

“To some extent, the loading method of Pt-alloy on carbon support, coupled with the quality of the raw materials, can determine the catalytic properties of the final product.91”

What the sources say

• ?Not checked — no full text of the sourcecites [91] Perego C., 1997, Catal. Today source

In the paper

“Also, it should be noted that during supported Pt-alloy catalyst formation, Park et al. 85 evidenced the presence of the interaction between metal precursor and carbon support in the carbon supported Pt-Ru system.”

What the sources say

• ?Not checked — no full text of the sourcecites [85] Park K.-C., 2010, J. Mater. Chem. source

In the paper

“Generally, Pt-alloy catalysts are deposited on nanostructured carbon support in order to increase the specific surface area, which is the prerequisite to obtain an acceptable catalytic performance.[58][59][60]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [58][59][60]

In the paper

“To improve the catalytic activity, stability, and utilization of Ptalloy catalysts, high surface area carbon black particles have been considered to be the best choice as the electrocatalyst support due to their large specific surface area favoring the dispersion of an active component, good electric conductivity, porous structure, and low cost.3,21,[52][53][54][55]”

What the sources say

• ?Not checked — no full text of the sourcecites [3] Wang Y.-J., 2011, Chem. Rev. source
• ?Not checked — no full text of the sourcecites [21] Fang B., 2011, J. Mater. Chem. source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [52][53][54][55]

In the paper

“In the synthesis process, catalyst particle size, shape/ morphology/nanostructure, and composition are critical factors for improving catalytic activity and stability.[33][34][35][47][48][49]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [33][34][35][47][48][49]

In the paper

“The enhanced catalytic activity resulted from the changes of physiochemical properties of Pt such as the change in Pt-Pt interatomic distance, the number of Pt nearest neighbors, the Pt 5d band vacancy, and the Pt-metal content on the particle surface.40”

What the sources say

• ?Not checked — no full text of the sourcecites [40] Antolini E., 2007, Appl. Catal. B Environ. source

In the paper

“Specifically in the XPS studies, the Pt 4f 7/2 in the carbon-supported Pt system, in particular with the Pt size in the 1-2 nm range, tended to shift to higher binding energies with respect to that of unsupported Pt due to the Pt-carbon electronic effect.[75][76][77][78]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [75][76][77][78]

In the paper

“In the carbon-supported Pt-alloy system, the interaction generally results from the electronic effect of Ptalloy clusters and carbon through electron transfer from Ptalloy clusters to oxygen atoms adsorbed on carbon surface since the electron was found transferred from Pt microdeposits to carbon.71,72”

What the sources say

• ?Not checked — no full text of the sourcecites [71] Fialkov A. S., 2000, Russ. J. Electrochem. source
• ?Not checked — no full text of the sourcecites [72] Escard J. J., 1973, Catalysis source

In the paper

“In current carbon-supported Pt (Pt-alloy) catalysts for PEMFC application, carbon support is well-known to play a key role in improving Pt utilization, ORR activity, and stability.15”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [15] Appleby, A. J.InThe Electrocatalysis of Fuel Cell Reactions;Dudley, R.; O’Grady, W.; Srinivasan, S., Eds.; The Electrochemical Society Softbound Proceedings Series, PV 79–2, Princeton, NJ, 1979; p23.

In the paper

“It has been found that the specific surface area, pore size distribution, and surface properties of carbon material strongly influence the size, size distribution of Pt-alloy particles, surface structure and morphology, and alloying degree and therefore the structure and morphology of the catalyst, affecting the number of the active sites on the catalyst surface and thus ORR activity in PEMFCs.94”

What the sources say

• ?Not checked — no full text of the sourcecites [94] Lavacchi A., 2013 source

In the paper

“They found that the deposition and dispersion of Pt and Pt-Ru nanoparticles were largely dependent on the surface chemistry of carbon support, which was closely related to the anchorage of metal precursor ions (i.e., precursor-support interaction [86][87][88][89][90] ) and nanoparticles.88,89”

What the sources say

• ?Not checked — no full text of the sourcecites [85] Park K.-C., 2010, J. Mater. Chem. source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [86][87][88][89][90]
• ?Not checked — no full text of the sourcecites [88] Aksoylu A. E., 2000, Appl. Catal., A source
• ?Not checked — no full text of the sourcecites [89] Prado-Burguete C., 1989, J. Catal. source

In the paper

“It has been reported in the literature [37][38][39][40][41][42][43][44][45][46] that when bifunctional Pt-alloys were used as cathode catalysts, the best performance was achieved by alloying Pt with first-row transition metals; [37][38][39][40] adding a third element to the respective binary catalysts for both anode and cathode materials has been attempted to attain higher catalytic performance.37”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [37][38][39][40]

In the paper

“Electron-spin-resonance (ESR) studies, for instance, clearly demonstrated electron donation by Pt to the carbon support.73”

What the sources say

• ?Not checked — no full text of the sourcecites [73] Hillenbrand L. J., 1965, J. Electrochem. Soc. source

In the paper

“At the same time, the solvent polarity can impose a significant influence on the deposition and dispersion of Pt-Ru nanoparticles on carbon support.90”

What the sources say

• ?Not checked — no full text of the sourcecites [90] Liang Y., 2005, Carbon source

In the paper

“These mismatches basically resulted from the differences in research conditions between the theoretical and experimental studies.”

In the paper

“The theoretical results from Matanovićet al. 170,174 showed higher ORR activity for the Pt:Ni ratio of 1:1 than the Pt:Ni ratio of 3:1”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Matanović et al. 170,174

In the paper

“Using the analysis of temperature-dependent oxygen reduction Tafel plot, they obtained the activation energies for the ORR on carbon-supported Pt-alloy catalysts in 0.1 M HClO 4 ,a s presented in Table 2, 171,172 and revealed the following order of increasing catalytic activity: Pt/C < Pt 3 Ni 1 /C < Pt 3 Co 1 /C < Pt 1 Co 1 /C.”

What the sources say

• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source
• ?Not checked — no full text of the sourcecites [172] Anderson A. B., 2005, J. Phys. Chem. B source

In the paper

“Using density functional theory (DFT) as a research approach, Nørskov et al. 131,132 demonstrated theoretically that electrocatalytic activity was significantly affected by nanoparticle size.”

What the sources say

• ?Not checked — no full text of the sourcecites [131] Nørskov J. K., 2008, Chem. Soc. Rev. source
• ?Not checked — no full text of the sourcecites [132] Meier J., 2004, Chem. Phys. Lett. source

In the paper

“the experimental results 175 in Strasser's group exhibited the reverse activity order: Pt 1 Co 1 /C < Pt 3 Co 1 /C.”

What the sources say

• ?Not checked — no full text of the sourcecites [175] Oezaslan M., 2012, J. Electrochem. Soc. source

In the paper

“the theoretical studies conducted by Paulus et al. 171 with the atomic ratio of Pt:Co from 3:1 to 1:1 showed that the catalytic activity increased in the order of Pt 3 Co 1 /C < Pt 1 Co 1 / C”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Paulus et al. 171

In the paper

“It should be noted that, in many cases, some mismatches exist between the theoretical and experimental studies on the ORR activity of carbon-supported Pt-alloy electrocatalysts.”

In the paper

“This clearly suggested that the Pt alloy's composition substantially affected its ORR activity.”

What the sources say

• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source
• ?Not checked — no full text of the sourcecites [172] Anderson A. B., 2005, J. Phys. Chem. B source

In the paper

“After the comparison of theoretical atomic densities and the experimentally determined active surface areas, they found that the difference in alloy composition and the corresponding hydrogen adsorption pseudocapacitance indeed influenced the number of Pt surface atoms and the surface composition.”

What the sources say

• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source

In the paper

“They found that the catalytic activity for Pt-Ni alloys increased in the order of Pt < Pt 3 Ni 1 <Pt 1 Ni 3 <Pt 1 Ni 1 , and they also confirmed that the Pt-Ni alloy catalyst with an atomic ratio of 1:1 had the maximum ORR activity.”

What the sources say

• ?Not checked — no full text of the sourcecites [174] Matanović I., 2011, J. Phys. Chem. C source

In the paper

“the experimental results from Sung's group 176 revealed that the ORR activity order was Pt 3 Ni 1 /C > Pt 1 Ni 1 /C.”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Sung's group 176

In the paper

“They found that the catalytic activity for Pt-Ni alloys increased in the order of Pt < Pt 3 Ni 1 <Pt 1 Ni 3 <Pt 1 Ni 1 , and they also confirmed that the Pt-Ni alloy catalyst with an atomic ratio of 1:1 had the maximum ORR activity.”

What the sources say

• ?Not checked — no full text of the sourcecites [174] Matanović I., 2011, J. Phys. Chem. C source

In the paper

“The catalytic performance of Pt-based catalysts was found to be dependent on their crystal facets.147”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source

In the paper

“It has been the durability issue of the PEMFC electrocatalyst with a carbon support that has been one of the most important challenges hindering PEMFC commercialization.”

In the paper

“The intermediate composition with a Pt:Ni ratio of 1:1 exhibited the highest ORR activity (see Figure 4).170”

What the sources say

• ?Not checked — no full text of the sourcecites [170] Wang C., 2012, ACS Catal. source

In the paper

“Wang et al. 155 reported the 5-and 9-fold enhancement of ORR activity for the Pt monolayer on Pd and Pd 3 Co cores.”

What the sources say

• ?Not checked — no full text of the sourcecites [155] Wang J.-X., 2009, J. Am. Chem. Soc. source

In the paper

“Typically, the reduction of the Pt precursor (e.g., platinum acetylacetonate, Pt(acac) 2 ) occurs faster than that of some 3d transition metals such as Mn, Fe, Ni, Co, and Cu, in the synthesis of carbon-supported Pt-alloy particles because Pt has a much higher reduction potential”

What the sources say

• ?Not checked — no full text of the sourcecites [170] Wang C., 2012, ACS Catal. source

In the paper

“This difference resulted from a volcano-shaped relationship between electrocatalytic activity and the electronic state of the atoms.”

What the sources say

• ?Not checked — no full text of the sourcecites [131] Nørskov J. K., 2008, Chem. Soc. Rev. source
• ?Not checked — no full text of the sourcecites [132] Meier J., 2004, Chem. Phys. Lett. source

In the paper

“A broad size distribution and relatively large particle size will lead to nonuniform chemical composition among alloy nanoparticles and thus decrease the catalyst's ORR activity.”

What the sources say

• ?Not checked — no full text of the sourcecites [199] Rao Ch. V., 2009, J. Phys. Chem. C source

In the paper

“Burst nucleation”

What the sources say

• ?Not checked — no full text of the sourcecites [181] Lamer V. K., 1950, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [193] Sugimoto T., 2000, Colloid Surf. A: Physicochem. Eng. Asp. source
• ?Not checked — no full text of the sourcecites [197] Peng X.-G., 1998, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [198] Reiss H., 1951, J. Chem. Phys. source

In the paper

“After the heat treatment, XRD spectra (see Figure 8A,B) indicated that the sizes of most of the particles had grown substantially, from 2. 7 to 10.6 nm (SA-15), 2.2 to 7.6 nm (OAM -15), and 2.5 to 5.0 nm (TOAB-15).”

What the sources say

• ?Not checked — no full text of the sourcecites [218] Kim J.-W., 2011, Int. J. Hydrogen Energy source

In the paper

“In these methods, protective agents, heat treatment temperature, reactant composition, and pH are the critical factors in controlling the size and morphology of synthesized nanoparticles.”

What the sources say

• ?Not checked — no full text of the sourcecites [4] Fang B., 2009, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [21] Fang B., 2011, J. Mater. Chem. source
• ?Not checked — no full text of the sourcecites [25] Kim M., 2010, Catal. Today source

In the paper

“Therefore, an appropriate particle size, especially 2-5 nm, is of key importance for Pt-alloy catalysts to achieve high ORR activity in PEMFCs.”

What the sources say

• ?Not checked — no full text of the sourcecites [121] Debe M. K., 2012, Nature source
• ?Not checked — no full text of the sourcecites [200] Okaya K., 2010, ACS Appl. Mater. Interfaces. source

In the paper

“Generally, particle size can be well controlled by tuning the concentration of the polymer stabilizer: 221,222 the better the stabilization effect (i.e., the higher the PVP concentration), the smaller the metal particles.”

What the sources say

• ?Not checked — no full text of the sourcecites [221] Semagina N., 2009, Catal. Rev. source
• ?Not checked — no full text of the sourcecites [222] Li H., 2007, J. Phys. Chem. C source

In the paper

“In the presence of citric acid, a series of Pt x Co y /C catalysts were prepared by borohydride reduction method.Based on the Debye-Scherrer equation, 217 all catalysts showed an average size of 6.0 nm.”

In the paper

“it was discovered that the D-Pt x Ni 1-x /C catalyst displayed the smallest particle size (∼4.7 ± 0.7 nm) among three Ni-rich dealloyed core-shell catalysts (D-PtNi/C, D-PtNi 3 /C, and D-PtNi 5 /C)”

What the sources say

• ?Not checked — no full text of the sourcecites [232] Gan L., 2012, Nano Lett. source

In the paper

“Obviously, the particle size considerably increases with the heat treatment temperature.”

In the paper

“it has been found that the ORR activity of PtM is at least twice that of pure Pt.”

What the sources say

• ?Not checked — no full text of the sourcecites [13] Gasteiger H. A., 2005, Appl. Catal. B: Environ. source
• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source
• ?Not checked — no full text of the sourcecites [249] Zhang J., 2005, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [250] Koh S., 2007, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [251] Mukerjee S., 1993, J. Electroanal. Chem. source
• ?Not checked — no full text of the sourcecites [252] Toda T., 1999, J. Electrochem. Soc. source
• ?Not checked — no full text of the sourcecites [253] Sung Y., 2011, Int. J. Hydrogen Energy source
• ?Not checked — no full text of the sourcecites [254] Jayasayee K., 2012, Appl. Catal. B Environ. source

In the paper

“It has thus been proven that pH is a key factor influencing the particle size of synthesized Pt-based nanoparticle catalysts.”

In the paper

“When a high surface area carbon (HSAC) was used as the support, they found that the particle size of the PtCo/C alloy increased from 3.6 to 4.0 nm as the Co to Pt ratio decreased from 3:1 to 1:3”

What the sources say

• ?Not checked — no full text of the sourcecites [175] Oezaslan M., 2012, J. Electrochem. Soc. source

In the paper

“The extended Pt 3 Ni (111) surfaces possessed enhanced ORR catalytic activity compared to stateof-the-art carbon-supported Pt nanoparticle catalysts.”

What the sources say

• ?Not checked — no full text of the sourcecites [286] Zhang J., 2010, Nano Lett. source

In the paper

“It is evident that, with a decrease in pH, the size of the Pt-Co alloy particles increased from 2.5 to 3.1 nm.”

What the sources say

• ?Not checked — no full text of the sourcecites [227] Kristian N., 2010, Electrochim. Acta source

In the paper

“With an initial pH of 9-10, the supported Pt-Ru catalyst had the smallest particle size.”

What the sources say

• ?Not checked — no full text of the sourcecites [25] Kim M., 2010, Catal. Today source

In the paper

“Composition is one of the most important factors affecting the size of as-synthesized Pt-alloy particles.”

What the sources say

• ?Not checked — no full text of the sourcecites [208] Zhang H., 2012, Chem. Soc. Rev. source
• ?Not checked — no full text of the sourcecites [226] Oh H. S., 2007, Electrochem. Acta source
• ?Not checked — no full text of the sourcecites [227] Kristian N., 2010, Electrochim. Acta source
• ?Not checked — no full text of the sourcecites [228] Ren G., 2007, Nanotechnology source
• ?Not checked — no full text of the sourcecites [229] Gan L., 2014, Top. Catal. source
• ?Not checked — no full text of the sourcecites [230] Lu J., 2014, Nat. Commun. source

In the paper

“Interestingly, Stamenkovic et al. 147 found that the different planes of a Pt alloy exhibited different ORR activities.”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source

In the paper

“It was concluded that the glycolate anion concentration determined the process of nucleation and growth.”

What the sources say

• ?Not checked — no full text of the sourcecites [225] Rusnaeni N., 2010, J. Appl. Sci. source
• ?Not checked — no full text of the sourcecites [226] Oh H. S., 2007, Electrochem. Acta source

In the paper

“The largest improvement in particle size reduction was observed in a pH range of 7-10.”

What the sources say

• ?Not checked — no full text of the sourcecites [225] Rusnaeni N., 2010, J. Appl. Sci. source

In the paper

“Among various carbon-supported PtM nanoparticle alloy catalysts, core-shell structured alloy catalysts with M or PtM alloy as the core and Pt as the shell have been found to exhibit considerably higher performance for the ORR than pure Pt/C.”

In the paper

“It is well-known that the mass activity of a catalyst for the ORR is inversely proportional to the particle size”

What the sources say

• ?Not checked — no full text of the sourcecites [244] Yano H., 2006, Phys. Chem. Chem. Phys. source

In the paper

“The intrinsic activity of Pt for the ORR of supported Ptalloy catalysts depended on both particle size and shape.”

What the sources say

• ?Not checked — no full text of the sourcecites [247] Kinoshita K., 1992
• ?Not checked — no full text of the sourcecites [248] Markovic N. M., 1997, J. Electrochem. Soc. source

In the paper

“They reported that the initial pH value in the starting solution had a significant influence on the Pt-Ru alloy particle size.”

What the sources say

• ?Not checked — no full text of the sourcecites [25] Kim M., 2010, Catal. Today source

In the paper

“However, after they are adsorbed onto specific facets of metal nanoparticles, inorganic species cannot afford the counterpart in the interaction to promote or inhibit further growth along given directions.295,314,315”

What the sources say

• ?Not checked — no full text of the sourcecites [295] Chen C., 2014, Science source
• ?Not checked — no full text of the sourcecites [314] Lee E. P., 2007, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [315] Lee E. P., 2006, Adv. Mater. source

In the paper

“It has been well evidenced that the catalytic activity of Pt-based nanocatalysts strongly depends on their crystal facets.147”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source

In the paper

“The population of the truncated-octahedral shape depended on the types and amounts of reducing and capping agents used.”

What the sources say

• ?Not checked — no full text of the sourcecites [288] Wu J., 2010, J. Am. Chem. Soc. source

In the paper

“Template assisted-synthesis approaches have been considered effective ways to prepare shape-controlled Pt-based alloys, evidenced by the successful synthesis of various Pt nanostructures, typically in polycrystalline form, using a template.[323][324][325][326]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [323][324][325][326]

In the paper

“Notably, this was the first time that PEO-PPO-PEO copolymer had been utilized as a reductant to prepare core-shell nanocrystals.”

In the paper

“However, the solute atoms are more likely to attach to less protected metal surfaces, resulting in anisotropic growth.”

In the paper

“The composition of the Pd@Pt nanocrystals determined the growth mode of the Pt shell and the corresponding morphology.”

In the paper

“Wu et al. 288 successfully prepared carbon-supported truncated-octahedral Pt 3 Ni (t,o-Pt 3 Ni) nanoparticle catalysts with a dominant exposure of {111} facets by a facile colloidal approach.”

What the sources say

• ?Not checked — no full text of the sourcecites [288] Wu J., 2010, J. Am. Chem. Soc. source

In the paper

“In addition to the use of different alkane chain lengths, a combination of strong (boranetert-butylamine complex, TBAB) and mild (hexadecanediol) reducing agents was used to effectively adjust the nucleation and growth rate.”

In the paper

“nontoxic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) [Pluronic F127 (PEO 100 PPO 65 PEO 106 )] amphiphilic triblock copolymer was used as the reducing agent, stabilizer, and capping agent to fabricate a dendritic core-shell structure.[307][308][309][310]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [307][308][309][310]

In the paper

“For a specific synthetic method, the specific facets in crystal growth dominantly determine the final shape of nanocrystals.181,[337][338][339][340]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites 181,[337][338][339][340]

In the paper

“concluded that the observed differences in the mass and area-specificO R R activities increased almost proportionally with the increase in the fraction of {111} surfaces over the entire surface areas of the carbon-supported Pt 3 Ni catalysts.”

What the sources say

• ?Not checked — no full text of the sourcecites [288] Wu J., 2010, J. Am. Chem. Soc. source

In the paper

“Hence, the design and synthesis of advanced Pt alloys with wellcontrolled shapes is very important for improving ORR activity.”

In the paper

“Using HRTEM and high-angle annular dark-field scanning TEM with an energy-dispersive X-ray (EDX) spectra (HAADF-STEM-EDX), two Pd-Pt bimetallic nanocrystals consisting of a Pd core and a Pt shell with different Pt/Pd molar ratios were identified (see Figure 15).”

In the paper

“The obtained shape of a Pt or Pt-alloy nanocrystals is a competition in surface energies among different facets because nanocrystal growth may occur by adatom incorporation perpendicular to high-energy crystal planes with a low stability.34,336”

What the sources say

• ?Not checked — no full text of the sourcecites [34] Porter N. S., 2013, Acc. Chem. Res. source
• ?Not checked — no full text of the sourcecites [336] Vitos L., 1998, Surf. Sci. source

In the paper

“Because the capping agent is adsorbed, the total excess free energy decreases, thus preventing the metal nanoparticles from further growth and aggregation.”

In the paper

“The final carbon supported Pt 3 Ni nanoframes showed more than 22 times the catalytic activity (5.7 A mg -1 Pt ) of conventional Pt/C catalyst at 0.9 V.”

What the sources say

• ?Not checked — no full text of the sourcecites [295] Chen C., 2014, Science source

In the paper

“Some Pt monolayer (Pt ML ) electrocatalysts have exhibited excellent activities because the interaction between the Pt monolayer and the substrate material induced a synergistic effect on the ORR kinetics.[350][351][352]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [350][351][352]

In the paper

“Based on density function theory (DFT) calculations, it was proven that the binding energies and reactivity of small adsorbates are strongly correlated with the position of the d-band center on strained surfaces and metal overlayers.[355][356][357]”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [355][356][357]

In the paper

“Recently, Chen et al. 295 obtained a nanoframed Pt 3 Ni/C catalyst by the control of structure at the atomic level.”

What the sources say

• ?Not checked — no full text of the sourcecites [295] Chen C., 2014, Science source

In the paper

“After post-treatment with Br -,P t ML /Br-treated Pd/C showed a 1.5-fold enhancement in specific and Pt mass activities for the ORR compared with Pt ML /Pd/C.”

What the sources say

• ?Not checked — no full text of the sourcecites [359] Cai Y., 2011, Langmuir source

In the paper

“It was found that the total noble-metal mass activity of (Pt 0.8 Re 0.2 ) ML /Pd 20 /C was 4-4.5 times higher than Pt/C commercial catalyst.249,349”

What the sources say

• ?Not checked — no full text of the sourcecites [249] Zhang J., 2005, J. Am. Chem. Soc. source
• ?Not checked — no full text of the sourcecites [349] Adzic R. R., 2007, Top. Catal. source

In the paper

“Also, the ORR mass activity (∼530 mA mg -1 Pt ) of carbon-supported Pt 3 Ni catalyst showed values that were 4 times higher than that of the standard Pt/C catalyst (∼140 mA mg -1 Pt ).”

What the sources say

• ?Not checked — no full text of the sourcecites [288] Wu J., 2010, J. Am. Chem. Soc. source

In the paper

“Okaya et al. 370 developed a two-step method to form a two-monolayer Pt-skin layer (Pt 2M L )o nP t x Co core particles supported on graphitized carbon black (GCB; see Figure 19).”

What the sources say

• ?Not checked — no full text of the sourcecites [370] Okaya K., 2012, ACS Appl. Mater. Interfaces source

In the paper

“Adzic et al. 360 also deposited amorphous Au clusters onto carbon-supported Pt nanoparticles through galvanic replacement reactions to mitigate the dissolution of Pt electrocatalysts; after potential cycling between 0.6 and 1.1 V for over 30 000 cycles, no loss in ORR activity was observed.”

What the sources say

• ?Not checked — no full text of the sourcecites [360] Zhang J., 2007, Science source

In the paper

“By comparing the surface properties of well-defined bulk PtNi (Pt-skeleton surface) and PtCo alloys (Pt-skin surface), Stamenkovic et al. 147 found that the ORR kinetics was dependent on the arrangement of Pt on the surface region.”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source

In the paper

“Beside the effect of facets on the ORR activity of Pt-Ni alloy supported on carbon, Wang et al. 155 also systematically investigated the effects of Pt shell thickness, facets, and particle size on the specific and mass activities via stepwise deposition of a Pt monolayer on Pd and Pd 3 Co cores.”

What the sources say

• ?Not checked — no full text of the sourcecites [155] Wang J.-X., 2009, J. Am. Chem. Soc. source

In the paper

“When Pt atoms deposit onto a foreign metal or alloy, the Pt surface undergoes compression or extension due to the difference in their atomic radii, inducing a D-band center shift and thus affecting the catalyst's activity.353”

What the sources say

• ?Not checked — no full text of the sourcecites [353] Xu Y., 2004, J. Am. Chem. Soc. source

In the paper

“To reduce Pt content and enhance catalytic activity, Adzic et al. 349 reported a series of Ptmonolayer fuel cell electrocatalysts, in which a Pt monolayer deposited on carbon-supported metal or metal-alloy nanoparticles resulted in the highest Pt utilization because almost every Pt atom on the surface participated in the electrocatalytic reactions.”

What the sources say

• ?Not checked — no full text of the sourcecites [349] Adzic R. R., 2007, Top. Catal. source

In the paper

“To obtain a typical coreshell structure for PtM alloy nanoparticles, one basic strategy is to introduce large amounts of M core particles into reaction mixtures in the presence of mild reducing agents or small amounts of Pt metal precursors.12”

What the sources say

• ?Not checked — no full text of the sourcecites [12] Peng Z., 2009, Nano Today source

In the paper

“The catalytic activity at different surfaces was in the order of Pt bulk < Pt-skeleton < Pt-skin.”

What the sources say

• ?Not checked — no full text of the sourcecites [147] Stamenkovic V. R., 2007, Science source

In the paper

“The ORR activity of this octahedral Pt 3 Ni catalyst (∼440 mA mg -1 Pt ) is about three times that of the reference Pt/C (∼140 mA mg -1 Pt ).”

What the sources say

• ?Not checked — no full text of the sourcecites [287] Wu J., 2011, Nano Lett. source

In the paper

“To solve this problem, Zhang et al. 286 used tungsten carbonyl (W(CO) 6 ) as the decelerator to develop the Pt 3 Ni nanooctahedra and nanocube with {111} facets and {100} facets exposed, respectively.”

What the sources say

• ?Not checked — no full text of the sourcecites [286] Zhang J., 2010, Nano Lett. source

In the paper

“At a similar size, a comparison of ORR activity between Pt 3 Ni nano-octahedra and nanocubes revealed that the former was ∼5-fold higher than the latter.”

What the sources say

• ?Not checked — no full text of the sourcecites [286] Zhang J., 2010, Nano Lett. source

In the paper

“Moreover, the electronic (ligand) effect from the electronic coupling between the Pt ML and its supporting substrate also plays a role in determining the catalytic activity.349,354”

What the sources say

• ?Not checked — no full text of the sourcecites [349] Adzic R. R., 2007, Top. Catal. source
• ?Not checked — no full text of the sourcecites [354] Cai Y., 2011, Adv. Phys. Chem. source

In the paper

“When evaluated in a 5 cm 2 single-cell test at 80 °C under H 2 /O 2 and 100% relative humidity, the preleached 50 wt % PtCo/C sample was found to have a mass activity of 360 mA mg -1 at 0.9 V.”

In the paper

“Pt ion is reduced more easily than other metal ions due to its higher standard reduction potential.300”

What the sources say

• ?Not checked — no full text of the sourcecites [300] Ferrando R., 2008, Chem. Rev. source

In the paper

“Interestingly, Jeon et al. 176 found that thermal treatment induced dealloying of carbonsupported Pt-Ni alloy nanoparticles with various compositions of 3:1, 1:1, and 2:3.”

What the sources say

• ?Not checked — no full text of the sourcecites [176] Jeon T.–Y., 2010, Electrochem. Commun. source

In the paper

“Wang et al. 376 synthesized a Pt 3 Co/C nanoparticle catalyst with a core-shell structure by a one-step impregnation reduction method [377][378][379][380][381] at different temperatures under a flowing H 2 /N 2 mixed gas atmosphere.”

What the sources say

• ?Not checked — no full text of the sourcecites [376] Wang D., 2013, Nat. Mater. source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [377][378][379][380][381]

In the paper

“Synthesis conditions, including temperature, time, the size of the other metal atom, and the ratio of starting materials, determine the local atomic arrangement in the Pt alloy.”

In the paper

“The formation of Pt alloys during the synthesis process is closely controlled by temperature.191,192,399”

What the sources say

• ?Not checked — no full text of the sourcecites [191] Porter D. A., 1992 source
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites [192] Mullin J. W., 1997
• ?Not checked — no full text of the sourcecites [399] Pfeiler W., 2007 source

In the paper

“It was found that PtM alloys with an atomic ratio of 3:1 exhibited 1.2-5.0times higher specific activity and mass activity than Pt/C.13,171,368,431,432”

What the sources say

• ?Not checked — no full text of the sourcecites [13] Gasteiger H. A., 2005, Appl. Catal. B: Environ. source
• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source
• ?Not checked — no full text of the sourcecites [368] Mukerjee S., 1995, J. Electrochem. Soc. source

In the paper

“Conversely, alloys will not form in a system that has a positive excess Gibbs free energy at a low synthesis temperature.”

In the paper

“In addition, the size difference between Pt and other metals can result in strain formation in Pt alloys, which is one of the most important factors affecting their catalytic activity toward oxygen reduction.24,252,400”

What the sources say

• ?Not checked — no full text of the sourcecites [24] Strasser P., 2010, Nat. Chem. source
• ?Not checked — no full text of the sourcecites [252] Toda T., 1999, J. Electrochem. Soc. source
• ?Not checked — no full text of the sourcecites [400] Jalan V., 1983, J. Electrochem. Soc. source

In the paper

“However, the alloy size of the preleached 50 wt % PtCo/C sample slightly increased from 2.9 to 4.2 nm when the thermal reduction temperature was changed from 600 to 800 °C.387”

What the sources say

• ?Not checked — no full text of the sourcecites [387] Stassi A., 2012, J. Power Sources source

In the paper

“Wang et al. 376 successfully synthesized an ordered Pt 3 Co alloy with an intermetallic core, and a platinum shell two to three atoms thick, using a colloidal method with H 2 PtCl 6 •H 2 O and CoCl 2 •H 2 O as the metal precursors.”

What the sources say

• ?Not checked — no full text of the sourcecites [376] Wang D., 2013, Nat. Mater. source

In the paper

“Furthermore, the areas of ordered arrangement or/and disordered arrangement in the composition of a Pt alloy play an important role in determining the catalytic activity of fuel cell electrocatalysts.263,376,401,402”

What the sources say

• ?Not checked — no full text of the sourcecites [263] Koh S., 2007, J. Power Sources source
• ?Not checked — no full text of the sourcecites [376] Wang D., 2013, Nat. Mater. source
• ?Not checked — no full text of the sourcecites [401] Xiong L., 2004, J. Mater. Chem. source
• ?Not checked — no full text of the sourcecites [402] Noh S. H., 2013, Nanoscale source

In the paper

“As the pH value decreased from 4 to 1.5, the crystal size of the Pt-Co alloy changed from 2.5 to 3.1 nm with a Pt to Co nominal molar ratio of 1:3.”

In the paper

“As with particle size and shape, alloy composition plays an important role in improving the catalytic performance of Ptalloy catalysts supported on carbon.”

In the paper

“It was found that after the preleaching step the alloy size of 50 wt % PtCo/C decreased from 3.1 to 2.9 nm, a finding verified through their TEM images.388”

What the sources say

• ?Not checked — no full text of the sourcecites [388] Aricò A. S., 2010, J. Phys. Chem. C source

In the paper

“In particular, the initial ratio of the starting materials dictates the Pt alloy's composition.”

In the paper

“Paulus et al. 171 studied carbon-supported Pt-Ni (molar ratio of Pt:Ni = 1:1) and carbon-supported Pt-Co (molar ratio of Pt:Co = 3:1) alloy catalysts, respectively, and found that in comparison with pure Pt the activity (per Pt surface atom) was enhanced ca.1.5 times for 25 at.% Ni or Co in Pt 3 M/C (M = Ni or Co) catalysts with 20 wt % metal loading.”

What the sources say

• ?Not checked — no full text of the sourcecites [171] Paulus U. A., 2002, J. Phys. Chem. B source

In the paper

“It is also evidenced in the literature 387,388 that under fuel cell operation the particle size and lattice parameters in crystal increased to some extent over time during the degradation test, indicating a moderate dealloying for the Pt-alloy catalyst with nonprecious metals like Co.”

What the sources say

• ?Not checked — no full text of the sourcecites [387] Stassi A., 2012, J. Power Sources source
• ?Not checked — no full text of the sourcecites [388] Aricò A. S., 2010, J. Phys. Chem. C source

In the paper

“They found that the reaction time was a critical parameter to tune the surface Pt:Ni composition and to optimize the ORR activity with a fixed molar ratio of Pt:Ni of 1:3.”

What the sources say

• ?Not checked — no full text of the sourcecites [433] Cui C., 2012, Nano Lett. source

In the paper

“Despite the exciting progress made in the past decade in terms of correlating the size, shape, and composition of carbonsupported Pt-based electrocatalysts with their electrocatalytic properties for the ORR, there is still a noticeable lack of mass production techniques for manufacturing high-quality, monodispersed Pt-alloy catalysts with optimized structural parameters, such as optimal size, des”

In the paper

“They examined the composition of PtM 3 using EDS (energy dispersive spectroscopy), XPS (X-ray photoelectron spectroscopy), and ICP-MS (inductively coupled plasma-mass spectroscopy; see Table 8) and found that the dissolution of 3d metals resulted in compositional changes.”

What the sources say

• ?Not checked — no full text of the sourcecites [259] Remona A. M., 2011, J. Fuel Cell Sci. Technol. source

In the paper

“It was concluded in this review refining the parameters of Pt-alloy nanoparticles (such as shape, size, and composition) could be used to precisely control their microstructure and properties and, consequently, to enhance the catalytic activity of electrocatalysts for the ORR.”

In the paper

“Particles with optimal size and uniform size distribution, coupled with desirable shape and composition, can yield a tremendous advantage over conventional Pt-alloy bulk catalysts in terms of ORR activity because of the former's much larger active surface area to volume ratio.”

In the paper

“(2) the PtCu 3 /C showed very poor performance, particularly at high current density (1.05A cm -2 at 0.6”

In the paper

“at 1 A cm -2 ,Pt 20 Cu 20 Co 60 /C (0.815 V) > Pt 20 Cu 40 Co 40 /C (0.808 V) > Pt 20 Cu 60 Co 20 /C (0.802 V)”

In the paper

“Improvement in the surface-area-normalized specific activity (∼0.248A cm -2 Pt ) was similar.”

What the sources say

• ?Not checked — no full text of the sourcecites [259] Remona A. M., 2011, J. Fuel Cell Sci. Technol. source

In the paper

“To date, significant progress has been made in the preparation and evaluation of Pt-based nanostructured alloy electrocatalysts, and their catalytic activities toward the ORR have been revealed to be strongly dependent on the size and size distribution, shape, and composition of the alloy nanoparticles.”

In the paper

“Therefore, significant challenges still remain in developing facile and efficient methods for the synthesis of a designed Pt-alloy nanostructure with uniform particle size, desirable shape, and favorable composition.”

In the paper

“For instance, the current density of PtNi 3 /C was about 1 A cm -2 at 0.7 V”

In the paper

“In general, the size and size distribution of Pt-alloy nanoparticles can be controlled at the molecular (nanometer) level.”

In the paper

“, 100% RH, 170 KPa, H 2 /air): (1) initial performance of PtNi 3 /C matched or exceeded that of Pt/C catalyst at all points of the polarization curve.”

In the paper

“These research results suggest that there is a close set of relationships among catalyst composition, dealloying time, and ORR activity.”

In the paper

“Table 2 . Activation Energies for the ORR on Carbon-Supported Pt-Alloy Catalysts in 0.1 M HClO 4”

• Also stated in: § 8. CONCLUSIONS · plain

  “Pt/C | 0.88 | 20 | 0.21”

• Also stated in: § 8. CONCLUSIONS · plain

  “Pt 3 Co/C | 0.88 | 28 | 0.29”

What the sources say

• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites Paulus et al. 171
• ?Not matched

  Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  cites ref 172

In the paper

“EDX analysis of the active ORRtested Pt-Ni electrocatalyst revealed that the final bulk composition of the Pt-Ni alloy had changed to about Pt 75 Ni 25 during the electrochemical dealloying process, similar to that of the ideal bulk composition of the highly active extended (111) surface.433”

What the sources say

• ?Not checked — no full text of the sourcecites [433] Cui C., 2012, Nano Lett. source